Electric heater for liquids



B. A. MIKKELSON ELECTRIC HEATER FORYLIQUIDS Filed May 14, 1958 Aug. 13,1940.

3mm/m Patented Aug. 13, 1940 'Unire www garant ortica ELECTRIC HEATER FRLIQUDS Berent A. Miklielson, Seattle, Wash.

Application May 14,

1 Ciaim.

The invention relates to electric heaters for liquids, such as water andoil, and has for an object the provision of an inexpensive device ofthis description useful in barber shops, homes 5 and other places forthe heating of water or as a pre-heater for the oil fed to oil burners,said heater being of comparatively small or portable nature connectibleto the ordinary light socket and operating efficiently at small cost forcurrent.

The invention consists in the novel construction and combinations ofparts as hereinafter set forth in the claim.

In the accompanying drawing:

Figure l is a central longitudinal section of the invention, and rFigure 2 is a cross section on the line 2-4-2, Figure 1.

In the drawing, the numeral I designates a tubular cylindrical metalliccasing, having a contracted forward end 2, provided with a centralaperture 3, a cylindrical heating element il being located within saidcasing and having an external diameter less than the internal diameterof the casing to provide a circumferential space 6 and an internaldiameter greater than the diameter of said aperture, a thermalinsulation lling of asbestos 'l being provided for said space. Theheating element has a central bore 5.

This heating element comprises a porcelain tube having a resistance wirecoil 8, surrounding and in contact with said tube, and a porcelain pasteexterior covering 9 for said wire coil, said porcelain paste coveringserving to insulate the coils from one another and to iirmly secure thecoils to the porcelain tube so that they cannot get out of place at anytemperature to which the coils may be raised and cause short circuiting.

The casing I has a lateral aperture I located near the rear end thereofand provided with an 40 eXteriorly threaded bushing I3, a junction box Mbeing secured to sai-d bushing by lock nuts l5. The lead-in wires I2 forthe resistance wire coil 8 are spliced within the junction boX andextend through the bushing-lined aperture I within said circumferentialspace 6, being secured at their inner ends to the screws l I of themetallic terminal bands II of the porcelain tube il, the opposite endsof the resistance wire coil 8 being also secured to the screws of saidbands. A removable closure I8 fits within the rear end of the casing I,abuts against the rear end of the porcelain tube 4I, has a centralaperture I8 of the same size as that of the forward end of said casingand closes in the rear end of the circumferential space 6. The closureI8 is held in Cil 1938, Serial No. 208,004

(Cl. 21S- 39) place by cotter pins I9 engaging perforations of the sidewall of said casing.

In assembling the parts, the heating element d is inserted within theopen rear end of the casing E until it contacts the contracted forwardend 2 of said casing, the lead-in wires I2 being then manipulatedthrough the bushing-lined lateral aperture of the casing into thejunction boX by inserting the lingers of one hand through the open rearend of the casing, said lateral aperture being located near the rear endof the casing to admit of such manipulation. The circumferential space lis then packed with the loose asbestos thermal insulating material l,thereby holding the tubular heating element d in central ized positionwithin the casing, the removable closure i3 fitting within the rear endof the casing and having a central aperture I8 being then placed inposition to abut against the rear end oi said heating element and toclose in the rear end of the thermal insulation packed circumferentialspace 6, said removable closure iS requiring nothing more than thecotter pins i9 engaging lateral perforations of the casing to hold it inplace.

Ilhe heater is adapted to have the pipe I'l for water cr oil to beheated extend slidably through the bore of the heating element orporcelain tube and the apertures of the ends oi the casing. Due to thefact that the porcelain tube 4 of the heating element has an internaldiameter greater than the apertures of the casing ends, acircumferential air space is provided between the pipe l'i and saidporcelain tube, thereby tending to protect the pipe il from beingsupercially fused or roughened by the heat and avoiding any suchadherence between the said porcelain tube and said pipe as wouldinterfere with free movement of the heater relative to said pipe.

The tubular casing i may be either cylindrical or other suitable shape,that is to say it may be square in cross section. The porcelain tube llmay be spirally grooved to receive the coils of the resistance wire coil8.

The heating device is held from rotation on the pipe l i for conv-eyingthe oil or water to be heated by electrical cable 2li carrying thelead-in wires l2, said cable having suitable lock-nut connection withthe junction box I4 and with the electrical outlet.

I claim:

In an electric heater for liquids, a tubular casing having a contractedforward end provided with a central aperture, a heating elementcomprising a porcelain tube having a resistance wire thermal insulationlling for said circumferential space adapted to hold said tube centralof said casing, a removable closure for the rear end of said casing,abutting against the rear end of said tube, closing in the rear end ofsaid circumferential space and having a central aperture of the samesize as that of said rst named aperture, said heater being adapted toprovi-de a circumferential air space between said tube and the pipe forconveying the liquid to be heated and engaged with the apertures of saidcasing ends, thereby tending to protect said pipe from being injured bythe heat and to render the heater freely movable at all times relativeto said pipe.

BEREN'I A. MIKKELSON.

